Mortgage Loans and Interest Rate Swaps (Details) $ in Thousands							1 Months Ended	12 Months Ended
	Jan. 23, 2020 USD ($) ft² building subsidiary	Dec. 20, 2019 USD ($) ft² subsidiary	Sep. 19, 2019	Mar. 29, 2018 USD ($) ft²	Jan. 30, 2018 USD ($) ft²	Mar. 15, 2017 USD ($) ft² building	Jun. 30, 2020 USD ($)	Nov. 30, 2020 USD ($) derivative item	Nov. 30, 2019 USD ($)	Nov. 30, 2018 USD ($)	Feb. 10, 2021 a	Aug. 01, 2019 USD ($)
Long-Term Debt
Loans, prior to debt issuance costs					$ 11,781
Loans, net of debt issuance costs								$ 161,048	$ 142,575
Interest rate (as a percent)				4.51%			3.50%
Debt disclosures
Term of debt							10 years	1 year
Amortization period of debt							25 years
New mortgage							$ 5,100
Number of buildings used as collateral | building						2
Proceeds from issuance of debt								$ 26,600	1,265	$ 31,623
Repayment of debt							$ 4,100
Interest expense								$ 7,281	$ 6,408	6,270
Minimum debt service coverage ratio								1.25	1.25
Maximum percentage of loan to value								65.00%	67.50%
Borrower deposited in escrow account								$ 1	$ 1
Escrow account balance								$ 300	200
Interest rate swap agreement
Debt disclosures
Number of agreements containing credit risk related contingent features | item								0
Loss expected to be reclassified over next twelve months from accumulated other comprehensive loss to interest expense								$ (1,975)
Net fair value of interest rate swap agreements								8,962	4,052
Recognized net losses (included in other comprehensive loss), before taxes, on interest rate swap agreements								$ 4,910	7,122	3,512
Number of interest rate swap derivatives | derivative								13
Interest expense								$ 1,438	32	$ 636
LIBOR
Debt disclosures
Variable interest rate margin (as a percent)							2.56%
Nonrecourse mortgage loans
Long-Term Debt
Loans, prior to debt issuance costs								163,185	144,473
Debt issuance costs, net								(2,137)	(1,898)
Loans, net of debt issuance costs								$ 161,048	$ 142,575
Weighted average interest rate								4.18%	4.31%
Annual principal payment requirements under the terms of the nonrecourse mortgage loans
2021								$ 5,108
2022								9,181
2023								5,451
2024								5,687
2025								21,009
Debt disclosures
Aggregate book value of land and buildings pledged as collateral								186,679
Construction loan
Debt disclosures
Construction loan with State Farm Life Insurance Company				$ 13,800
Area Of Building | ft²				234,000
Amortization period of debt				25 years
Acquisition Credit Line
Long-Term Debt
Weighted average interest rate			4.57%
Debt disclosures
Minimum debt service coverage ratio			1.25
Acquisition Credit Line | LIBOR
Debt disclosures
Variable interest rate margin (as a percent)			2.75%
4.72%, due October 3, 2022
Long-Term Debt
Loans, prior to debt issuance costs								$ 4,070	$ 4,174
Interest rate (as a percent)								4.72%	4.72%
4.39%, due January 2, 2025
Long-Term Debt
Loans, prior to debt issuance costs								$ 18,503	$ 19,101
Interest rate (as a percent)								4.39%	4.39%
4.17%, due May 1, 2026
Long-Term Debt
Loans, prior to debt issuance costs								$ 12,730	$ 13,115
Interest rate (as a percent)								4.17%	4.17%
3.79%, November 17, 2026
Long-Term Debt
Loans, prior to debt issuance costs								$ 23,973	$ 24,701
Interest rate (as a percent)								3.79%	3.79%
4.39%, due August 1, 2027
Long-Term Debt
Loans, prior to debt issuance costs								$ 9,772	$ 10,034
Interest rate (as a percent)								4.39%
3.97%, due September 1, 2027
Long-Term Debt
Loans, prior to debt issuance costs								$ 11,439	$ 11,673
Interest rate (as a percent)								3.97%	3.97%
4.57%, due February 1, 2028
Long-Term Debt
Loans, prior to debt issuance costs					$ 11,781			$ 17,639	$ 18,069
Interest rate (as a percent)								4.57%	4.57%
Debt disclosures
Term of debt								10 years
Area of collateralized properties (in square feet) | ft²					137,000
Proceeds from issuance of debt					$ 7,000
Fixed interest rate pursuant to interest rate swap agreement (as a percent)					4.57%
5.09%, due July 1, 2029 GCD mortgage loan
Long-Term Debt
Loans, prior to debt issuance costs								$ 5,254	$ 5,725
Interest rate (as a percent)								5.09%	5.09%
5.09%, due July 1, 2029 TD mortgage Loan
Long-Term Debt
Loans, prior to debt issuance costs								$ 3,681	$ 4,011
Interest rate (as a percent)								5.09%	5.09%
3.60%, due January 2, 2030
Long-Term Debt
Loans, prior to debt issuance costs								$ 6,364
Interest rate (as a percent)								3.60%	3.60%
Debt disclosures
Term of debt		10 years
Amortization period of debt		25 years
New loan		$ 6,500
Area of collateralized properties (in square feet) | ft²		100,000
Repayment of debt		$ 5,875
Number of subsidiaries which are party to the mortgage | subsidiary		2
3.60%, due January 2, 2030 | Interest rate swap agreement
Debt disclosures
Fixed interest rate pursuant to interest rate swap agreement (as a percent)		3.60%
3.60%, due January 2, 2030 | LIBOR
Debt disclosures
Variable interest rate margin (as a percent)		1.75%
3.48% due February 1 2030
Long-Term Debt
Loans, prior to debt issuance costs								$ 14,714
Interest rate (as a percent)	3.48%							3.48%	3.48%
Debt disclosures
Term of debt	10 years
Amortization period of debt	25 years
New mortgage	$ 15,000
Number of buildings used as collateral | building	2
Area of collateralized properties completed (in square feet) | ft²	254,000
Repayment of debt	$ 3,191
Number of subsidiaries which are party to the mortgage | subsidiary	2
3.50%, due July 1, 2030
Long-Term Debt
Loans, prior to debt issuance costs								$ 5,057
Interest rate (as a percent)								3.50%	3.50%
4.33%, due August 1, 2030
Long-Term Debt
Loans, prior to debt issuance costs								$ 16,274	$ 16,634
Interest rate (as a percent)								4.33%
4.51%, due April 1, 2034
Long-Term Debt
Loans, prior to debt issuance costs								$ 13,715	$ 14,030			$ 14,107
Interest rate (as a percent)								4.51%	4.51%
3.91%, due January 27, 2020
Long-Term Debt
Loans, prior to debt issuance costs									$ 3,206
Interest rate (as a percent)								3.91%	3.91%
2017 PUB Mortgage
Debt disclosures
Term of debt						10 years
Amortization period of debt						25 years
New mortgage						$ 12,000
Area of collateralized properties (in square feet) | ft²						275,000
2017 PUB Mortgage | LIBOR
Debt disclosures
Variable interest rate margin (as a percent)						1.95%
Subsequent events
Debt disclosures
Build-to-suit industrial / warehouse building (in acres) | a											91